Think you know gin? Well, here's a true test: try and name all 400 of the ones available from Holborn Dining Room's new gin bar. If you manage it, we'll be extremely impressed. The collection is London's largest, and you'll be able to sample each and every one of them with selection of 27 tonics, or even the one made in house according to a top-secret recipe. This means the possibilities are endless. Well, almost – the bar worked it out as 14,035 possible gin pairings. It might take you a while to get through all those, then. Gins to look out for are Forest Dry: Spring, an eco-friendly brand making its spirits with seasonal botanicals grown at its distillery, and the cognac-based Pink-Pepper gin if you like your G&Ts with a kick.